Zero-day sales not 'fair' - to researchers

So how much is a vuln worth... and who's buying?

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Two years ago, Charles Miller found a remotely exploitable flaw in a common component of the Linux operating system, and as many enterprising vulnerability researchers are doing today, he decided to sell the information.

Having recently left the National Security Agency, the security professional decided to try his hand at selling the bug to the U.S. government. In a paper due to be presented next week at the Workshop on the Economics of Information Security, Miller - now a principal security analyst at Independent Security Evaluators - writes about the experience and analyzes the market for security vulnerabilities.

In the case of the Linux flaw, one agency offered him $10,000, while a second told him to name a price. When he said $80,000, his contact quickly agreed.

"The government official said he was not allowed to name a price, but that I should make an offer," Miller told SecurityFocus. "And when I did, he said OK, and I thought, 'Oh man, I could have gotten a lot more.'"

The sale underscores a significant problem for vulnerabilities researchers that attempt to sell a flaw: Determining the value of the information. In addition, time is a major factor: Miller felt pressured to complete the deal, because if anyone else found and disclosed the flaw, its value would plummet to zero. In a second attempted sale outlined in the paper, the disclosure clock ran out for Miller as he tried to sell a PowerPoint flaw that Microsoft patched this past February before the researcher could close the deal.

Yet, researchers that sell vulnerabilities should also consider the ethical issues involved, said Terri Forslof, manager of security response for TippingPoint, a subsidiary of networking giant 3Com.

"The value of the vulnerability is determined by the amount of time that the vulnerability can be used to get a return on investment before it is patched," Foslof said. "If I'm paying $50,000 for a vulnerability, what am I doing with it? I'm likely not trying to get it patched."

Miller found out that selling a flaw for a fair price is difficult. While the unnamed government agency offered the researcher $80,000, they placed a condition on the sale that the exploit would have to work against a particular flavor of Linux. Two weeks later and worried that the flaw might be found, Miller accepted a lesser offer from the same group for $50,000 for the exploit as is.

"While I was paid, it wasn't a full success," he wrote in the paper (PDF). "First, I had no way to know the fair market value for this exploit. I may have been off by a factor of ten or more."

Moreover, Miller had contacts in the government, but could not initially find the right people with which to deal. So, he offer a 10 percent cut to a friend who had better contacts. Other researchers might not be able to find the right contacts to complete similar deals.

"The only reason this sale happened at all was because of personal contacts I had, which should not be necessary for a security researcher who wants to make a living," he wrote in the paper.